Peng Qingcai and his sister He lived in the Tuen Mun section of Hong Kong with their mother. It is an area with a reputation for poverty and crime. Somehow they became acquainted with Madeline Bosch, perhaps by meeting at a mall. She referred to Peng as Quick. Maddie was really friends with He, but Peng often hung out with them. There were some things about Peng that may have attracted Maddie. He was older (about 17), he smoked, had tattoos and owned a car. These same things would have disturbed both Bosch and Wish if they had known about him.
At some point in the summer of 2009 Madeline enlisted Peng and He in a plan to get her father to come to Hong Kong and take her back to L.A. The original plan was to fake the abduction of Madeline. However, Peng apparently wanted to join a Triad, and he conspired with unknown Chinese crimials to actually kidnap her. After the kidnapping the criminal organization apparently viewed Peng and He as liabilities. Peng, He and their mother were murdered and left in the bathroom of their apartment.